When a vehicle is involved in a frontal impact, the steering column tends to rise. In other words, the steering column, which normally is inclined upwardly and rearwardly at a predetermined angle, will rise to a greater angle upon frontal impact. This is caused by the vehicle engine being thrust rearwardly.
The rise in the steering column places the steering wheel/air bag assembly in an unfavorable position relative to the driver's chest. When the driver's chest comes into contact with the steering wheel/air bag assembly, the force against this assembly has a considerable off-axis bending component which is increased due to the rise in the steering column. If the rise in the steering column is such that the off-axis component of force on the steering wheel/air bag assembly acts above the center of mass of the driver's chest, then the driver tends to move under the steering wheel, creating an even less favorable situation.
In accordance with the present invention, support structure is provided to insure that there is no appreciable upward rise or tilt of the steering column upon frontal impact. Preferably the steering column support structure includes a bracket in the form of a molded plastic frame having a pair of side braces interconnected by a transverse front brace and a transverse intermediate brace. An X-shaped truss has first and second legs extending diagonally between the side braces between the intermediate brace and the rear ends of the side braces.
Each side brace includes one and preferably two side trusses located between the intermediate brace and the rear ends of the side braces, and a third side truss between the intermediate brace and the front brace. Preferably a pair of mounting ears projects from the side braces for mounting purposes. A plurality of metal fastener inserts may also be molded into the frame for attachment purposes.
The bracket of this invention also provides the necessary rigidity to prevent undesirable vibration of the steering column during normal operation of the vehicle.
One object of this invention is to provide a steering column support structure having the foregoing features and capabilities.
Another object is to provide a steering column support structure which is composed of a bracket in the form of a relatively inexpensive molded plastic frame that is strong and durable and well adapted to the accomplishment of its intended function.
Other objects, features and advantages of the invention will become more apparent as the following description proceeds, especially when considered with the accompanying drawings.